As is well known, a plasma display device realizes an image on a plasma display panel (PDP) by employing plasma generated from gas discharge. Hence, the PDP produces a considerable amount of heat because of the high-temperatures involved when performing gas discharge.
As a discharge rate of a plasma display device is increased to improve brightness, the heat generated at the PDP also increases. It is, therefore, essential to effectively dissipate the heat to outside the plasma display device to maintain good operation.
For that reason, a PDP in a conventional plasma display device is usually attached to a chassis base formed out of materials having a high degree of thermal conductivity, and a heat spreading sheet (or a thermally conductive sheet) is interposed between the PDP and the chassis base. As a result, the heat generated at the PDP can be dissipated to outside the plasma display device via the heat spreading sheet and the chassis base. The chassis base is typically formed by a die casting or press working process using a metallic material such as aluminum. The heat spreading sheet is typically formed of acryl or a silicone-based resin.
To improve the efficiency of the heat dissipation of the plasma display device as described above, it is important to effectively mount the heat spreading sheet. That is, the heat spreading sheet should be brought into substantially close contact with both the PDP and the chassis base in order to improve the heat dissipation efficiency.
Since the chassis base is produced by die casting, the surface thereof contacting the heat spreading sheet may not be formed sufficiently flat, and instead may be formed with a partially curved or raised portion. When the heat spreading sheet is attached to such an uneven surface of the chassis base, spaces are formed between the contact surfaces of the heat spreading sheet and that of the chassis base. Air fills these spaces to form an air gap.
If the plasma display device is manufactured with an air gap between the chassis base and the heat spreading sheet, an overall heat dissipation efficiency will be reduced because good heat conduction does not occur through the air gap. Such a problem may also occur at portions where the PDP and the heat spreading sheet contact.
To resolve the above problems, Japanese Patent Publication Laid-Open No. 10-172446 discloses a plasma display device, in which the heat dissipation efficiency is improved by attaching a panel to a thermally conductive medium. The thermally conductive medium is formed by the process of providing a cushioning medium in a rectangularly annular shape at a chassis member, and injecting a liquid of a thermally conductive medium into a region surrounded by the cushioning medium, after which the liquid is cured.
In the process of manufacturing the plasma display device as described above, the thermally conductive medium lacks fluidity while being attached to the panel because the liquefied thermally conductive medium is cured and then attached to the panel. Hence, the adhesion rate is not much higher than that of the conventional heat spreading sheet.
Silicone tape is further required for a cushioning medium, and double-sided tape is also required in order to attach the panel to the chassis member. The process of manufacturing the plasma display device according to the above-described method, therefore, involves high costs.